1. Field of the Invention
The present invention relates to an electronic blood pressure monitor, and more particularly to an electronic blood pressure monitor capable of calculating an average value of measured blood pressure data.
2. Description of the Background Art
In recent years, many people suffer from lifestyle diseases caused by hypertension, and blood pressure management using a blood pressure level as an index for health care is important. The blood pressure, however, readily fluctuates depending on life environment and stress. Therefore, in blood pressure measurement, trend management or a management method using an average value, without nervously reacting to a blood pressure level for each measurement, is useful. As such, the following techniques have conventionally been proposed.
For example, according to the disclosure of Japanese Patent Laying-Open No. 2002-102184, inflation/deflation of an air bag (cuff) is automatically repeated for two or more cycles, preferably three cycles, and respective average values of maximal blood pressure (systolic blood pressure), minimal blood pressure (diastolic blood pressure) and pulse rate/minute measured for each cycle as well as a maximum deviation between the measured value and the average value are automatically calculated and displayed at the end of the last cycle. In addition, according to the disclosure, the number of cycles to be repeated can be set in advance.
Moreover, Japanese Patent Laying-Open No. 06-217949 discloses the following technique. Specifically, blood pressure is successively measured at each measurement point first predefined number of times in a relatively short period of time during which fluctuation of blood pressure caused by a living body is less likely. If fluctuation of the blood pressure levels obtained by measurement conducted first predefined number of times or obtained by measurement conducted second predefined number of times not as great as the first predefined number of times is within a predefined range, it is determined that reliable measurement has been conducted. If it is determined that measurement is reliable, an average value of the blood pressure levels obtained by measurement conducted second predefined number of times is employed as measurement data, and a circadian rhythm regression curve of the blood pressure is found. On the other hand, if fluctuation of the blood pressure levels obtained by measurement conducted the second predefined number of times is not within a predefined range in repeated measurement conducted first predefined number of times, the blood pressure levels as many as the second predefined number, of which value is close to that of the blood pressure levels obtained by measurement conducted first predefined number of times, are selected from the blood pressure levels obtained by measurement conducted first predefined number of times, the average value of the selected blood pressure levels is employed as measurement data, and a circadian rhythm regression curve of the blood pressure is found.
According to the techniques as described above, however, data including data chronologically measured when a mental and physical condition of a subject or an ambient environment is different are averaged, and that average is used as the evaluation index. In addition, a time period during which the subject is engaged in successive measurement becomes longer, which leads to lower blood pressure measurement compliance of the subject.